Pentagon-backed scientists on Monday announced they had created a robot
hand that was the most advanced brain-controlled prosthetic limb ever
The mind-powered prosthesis is a breakthrough, the team of neurologists and bio-engineers reported in The Lancet.
further development "individuals with long-term paralysis could recover
the natural and intuitive command signals for hand placement,
orientation and reaching, allowing them to perform activities of daily
living," they said.
Researchers have long been interested in the
brain-machine interface, whereby implants pick up electrical signals in
parts of the brain associated with movement.
These signals are then transcribed into computer code, which orders the artificial limb to move.
new work vastly improves the code, or algorithm, by which the first
signal is transcribed into the second, the investigators said.
of the biggest challenges has always been how to translate brain
signals that indicate limb movement into computer signals that can
reliably and accurately control a robotic prosthesis," said Andrew
Schwartz, a professor of neurobiology at the university.
mind-controlled prosthetics have achieved this by an algorithm which
involves working through a complex 'library' of computer-brain
connections," he said.
"However, we've taken a completely
different approach here, by using a model-based computer algorithm which
closely mimics the way that an unimpaired brain controls limb movement.
The result is a prosthetic hand which can be moved far more accurately
and naturalistically than previous efforts."
The team, based at
the University of Pittsburgh in Pennsylvania, implanted two
microelectrode arrays into the left motor cortex of a 52-year-old woman.
had been left paralysed from the neck down, unable to move her arms and
legs due to a condition called spinocerebellar degeneration.
weeks after the operation, the prosthesis was connected and the woman
embarked on 14 weeks of training but on only the second day, she was
able to move the limb through mind power.
The training aimed at
achieving skills in nine tasks, such as gripping and moving small
objects, stacking cones and bumping a ball so that it rolled outside a
loose coil of wire.
At the end, the volunteer completed the tasks
with a success rate of up to 91.6%, and more than 30 seconds faster than
at the start of the trial.
The researchers said they were sure
this is a success as they used an exhaustive benchmark test designed to
identify genuine changes and root out flukes or anecdotal evidence.
next steps are likely to see a robot limb incorporate sensors to tell
the patient whether a surface is hot or cold or rough or smooth, and to
use wifi, rather than a wire, to connect the patient's skull and the
In October 2011, a team at Duke University in North
Carolina reported that they had implanted brain electrodes in monkeys
that enabled the animals to sense the texture of a virtual object.
of the funders of the latest study is the Defence Advanced Research
Projects Agency (DARPA), a branch of the US Department of Defence that
looks into futuristic technology with a potential military use,
including by wounded veterans.